Talk:Schwinger limit

A fact from Schwinger limit appeared on Wikipedia's Main Page in the Did you know column on 1 July 2012 (check views). The text of the entry was as follows:

Did you know... that light can elastically scatter other light (Feynman diagram pictured) if the electric field strength exceeds the Schwinger limit?

A record of the entry may be seen at Wikipedia:Recent additions/2012/July. The nomination discussion and review may be seen at Template:Did you know nominations/Schwinger limit.

Wikipedia

Intuitive explanation[edit]

Is the required field...intense? Could we get an intuitive ballpark estimate of how intense? -- Beland (talk) 18:21, 6 February 2014 (UTC)[reply]

Very intense. I'm no physicist (just passing by), but have an amateur interest ... Air breaks down (so, when sparks form) at 30 kV/cm^[1] or 3x10⁶ V/m. So given that the Schwinger limit is at around 10¹⁸ V/m, that's a long way to go (about 1,000,000,000,000 times larger). Klbrain (talk) 22:50, 22 May 2017 (UTC)[reply]

References

^ J. J. Lowke (1992). "Theory of electrical breakdown in air" (PDF). Journal of Physics D: Applied Physics. 25 (2): 202–210. Bibcode:1992JPhD...25..202L. doi:10.1088/0022-3727/25/2/012.

Schwinger magnetic induction[edit]

I have not been able to find anything that would indicate that the Schwinger magnetic induction is a defined concept in the scientific world. The history of the section (from before it was merged) suggests that it was not based on anything solid to start with. If we do not have any reference to define it, perhaps it does not belong here. —Quondum 01:56, 7 May 2020 (UTC)[reply]

Wolfram is considered to be a RS. Xxanthippe (talk) 22:36, 7 May 2020 (UTC).[reply]

By whom? By what criteria? Perhaps you can point out where in WP:RS it defines an online query engine (in this instance WolframAlpha) that provides some answer to a best-guess interpretation of a phrase as a source at all? —Quondum 02:19, 8 May 2020 (UTC)[reply]

I suggest you open a RfC on the matter. In respect to your edit summary I remind you of WP:Civil. Xxanthippe (talk) 08:02, 8 May 2020 (UTC).[reply]

I see no reason to regard WolframAlpha's attempt to parse natural language and cough up a mathematical answer as a reliable source for an encyclopedia article. In this particular case, the term "Schwinger magnetic induction" is almost unattested in the scientific literature — two Google Scholar hits, which actually resolve to the same paper from 2017. (And since that is more recent than the introduction of the term on Wikipedia, we can't discount the possibility of citogenesis. For all we know, WolframAlpha is using Wikipedia/Wikidata information in its parsing, too.) XOR'easter (talk) 22:25, 9 May 2020 (UTC)[reply]

I think the concept is notable enough; it is the terminology that is difficult. This is the kind of thing that is studied by particle physicists, who seem to largely use the Gaussian system of quantities and units, in which magnetic field strength and magnetic flux density (these terms are from the 9th SI Brochure) are not distinguished, leading to terminological problems when trying to translate to SI, and there is the widespread problem that the terms magnetic flux density, magnetic induction and magnetic field strength are used for the "B-field", the latter also being used for the "H-field". This hints that the most common term in particle physics might be "magnetic field strength". With this insight, we can search for "Schwinger magnetic field" on Google books and Google scholar and get some hits. It seems to have a few names, including "critical magnetic field". It seems to be an active field of research: though the electric field at the Schwinger limit is difficult to attain (the vacuum state generates electron–positron pairs which then avalanche before it is reached), around the critical magnetic flux density the vacuum state becomes very nonlinear to photons, and this magnetic flux density is exceeded both on magnetars and in LHC heavy-ion collisions. As an exercise in jaw-dropping, calculate the mass-density-equivalent of the magnetic field energy density for the strongest magnetars.

In the context of WP, I would lean towards SI terminology. Terminology from Gaussian units is inviting confusion in the context of a general encyclopaedia, where few of the readers are as familiar with Gaussian units as with SI units, and one can see the amount of ongoing confusion that it causes between editors of physics articles. —Quondum 15:45, 10 May 2020 (UTC)[reply]

Yes, I think the issue is with the terminology rather than the concept; the main issue is that Wikipedia shouldn't be using and bolding jargon that scientists don't actually employ. "Schwinger magnetic field" seems to have at least two different meanings, the one referred to here and one relevant in neutron-diffraction studies for crystallography. "Critical magnetic field" more often refers to superconductors, I believe. Perhaps we should just say "the magnetic field strength corresponding to the Schwinger limit", or something like that. XOR'easter (talk) 19:43, 10 May 2020 (UTC)[reply]

I agree with your approach. I've edited it accordingly. I think this article should be merged into Vacuum polarization (see this is covered in Vacuum polarization § Electric and magnetic fields). —Quondum 21:47, 10 May 2020 (UTC)[reply]

Distinction between Schwinger field and Critical Field in Classical Electrodynamic[edit]

The current article uses the wrong notation for the Schwinger field. E_c and B_c are the critical field in classical electrodynamics. That is what by convention is used. I tried to add a section outlining the distinction with sources. But the user @Xxanthippe reverted the edit.

I do Physics and my work connected with this, so if the issue is that my edit was confusing. Maybe I should receive productive comments rather than just a revert. What was confusing? What needed to be expanded?

As the article stands now, E_c and B_c are wrong. They refer to a different field strengths. This is what is used throughout literature.

Considering this article is a Start-class article, it still needs further information in it.

I can expand the article better, if my original edit was confusing, but feedback will be appreciated instead of a full revert. Just to quote the wiki on reverting :"Consider carefully before reverting, as it rejects the contributions of another editor, and all others' after the edit in question. Consider what you object to, and what the editor was attempting. Can you improve the edit, bringing progress, rather than reverting it? Can you revert only part of the edit, or do you need to revert the whole thing? (The latter option is better executed through an undo action.) [[1]]"

Pablojbilbao (talk) 22:02, 11 April 2024 (UTC)[reply]

You will need to produce sources that support your view and support from other editors per WP:BRD. Xxanthippe (talk) 22:54, 11 April 2024 (UTC).[reply]

I provided sources and included them in the citations. Would you kindly outline what was the confusing part? I will eventually get around rewriting the small addition I added. Pablojbilbao (talk) 16:17, 19 April 2024 (UTC)[reply]

[1] J. J. Lowke (1992). "Theory of electrical breakdown in air" (PDF). Journal of Physics D: Applied Physics. 25 (2): 202–210. Bibcode:1992JPhD...25..202L. doi:10.1088/0022-3727/25/2/012.

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